X-linked ARSL chondrodysplasia punctata: expanding the spectrum with a severe multisystem phenotype.

Objectives: X-linked chondrodysplasia punctata type 1 (CDPX1) is a rare skeletal dysplasia caused by pathogenic variants in ARSL (Arylsulfatase L), formerly known as ARSE (Arylsulfatase E), resulting in defective arylsulfatase E activity and abnormal cartilage matrix formation. It is typically defined by stippled epiphyses, nasomaxillary hypoplasia, and brachytelephalangy, but the condition has phenotypic variability. We report an infant with a pathogenic ARSL variant (NM_000047.3:c.1442C>T; p.Thr481Met) to highlight an exceptionally severe and complex phenotype. Case presentation: A male infant was born at term following a caesarean section. A narrow sacral spine, a flat facial profile and an absent nasal bridge had been detected antenatally. He developed refractory respiratory failure with recurrent lung collapse and pneumothoraces in the first 3 months, associated with diffuse tracheobronchial calcification and progressive high cervical myelopathy on radiological evaluation. From 5 months of age, he experienced episodes of abrupt cardiorespiratory arrest linked to movement. Stabilisation of the neck markedly reduced those events temporarily, implicating dynamic cervical cord compression as the precipitating mechanism. He required prolonged mechanical ventilation, had recurrent infections and progressive neurological impairment and hydrocephalus warranting long term respiratory and neurosurgical follow up. This case represents one of the first descriptions of movement-related autonomic reflex asystole secondary to cervical cord compromise in ARSL-related CDPX1. Conclusions: Our report broadens the clinical spectrum of CDPX1 to include dynamic cervical cord compression with potential secondary autonomic cardiac events. Early genetic confirmation, anticipatory airway and spinal imaging, extensive respiratory and multidisciplinary management are essential for early recognition, prognostication and prevention of potentially fatal outcomes in severe forms of this rare disorder.